Hypertonic saline increases gammadeltaT cell-mediated killing of activated neutrophils.
OBJECTIVE
Hypertonic saline fluids used to resuscitate trauma patients can prevent neutrophil-mediated lung tissue damage, making them attractive alternatives to conventional resuscitation fluids. We have previously shown that gammadeltaT cells, a small T lymphocyte subset, reduce acute inflammatory lung damage by eliminating activated neutrophils that express heat shock protein 72 on the cell surface. Here, we studied whether these protective effects of hypertonic saline are related to improved gammadeltaT cell-mediated neutrophil killing.


METHODS
Laboratory investigation.


METHODS
University research laboratory.


METHODS
Human peripheral blood from healthy subjects--isolated gammadeltaT lymphocytes and neutrophils.


METHODS
Isolated blood cells were treated with different concentrations of hypertonic saline and endotoxin of Escherichia coli O111:B4 (lipopolysaccharide). In some experiments, gammadeltaT cells were activated by CD3 cross-linking or by phorbol-myristate acetate and ionomycin, or by phytohemagglutinin.


RESULTS
Clinically relevant concentrations of hypertonic saline (20 mM) significantly augmented CD69 expression of gammadeltaT cells that were stimulated with 100 ng/mL lipopolysaccharide. Additionally, lipopolysaccharide induced a three- to five-fold increase in tumor necrosis factor-alpha and interleukin-10 expression by gammadeltaT cells. This response was completely abrogated by hypertonic saline. These data indicate that hypertonic saline can modulate gammadeltaT cell functions. Stimulation of neutrophils with 1-1,000 ng/mL lipopolysaccharide caused a greater than 3-fold increase in heat shock protein-72 expression on the cell surface, which was significantly augmented by hypertonic saline. In cocultures of gammadeltaT cells with autologous neutrophils, 15.6 +/- 3.4% of all neutrophils were killed within 120 min. In the presence of lipopolysaccharide (1 microg/mL), this percentage increased to 23.7 +/- 2.1%, and it was further increased to 31.8 +/- 3.1% when 20 mM hypertonic saline was added with lipopolysaccharide.


CONCLUSIONS
Our findings suggest that hypertonic saline enhances the elimination of inflammatory neutrophils by gammadeltaT cells by augmenting heat shock protein-72 expression on the cell surface of neutrophils. Hypertonic saline resuscitation may therefore protect host tissues by enhancing neutrophil clearance from the lungs.
Hirsh
Mark I
MI
Department of Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
Hashiguchi
Naoyuki
N
Junger
Wolfgang G
WG
D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D066298:In Vitro Techniques; D016753:Interleukin-10 / Q000096:biosynthesis; D037181:Lectins, C-Type; D008070:Lipopolysaccharides / Q000494:pharmacology; D018375:Neutrophil Activation; D009504:Neutrophils / Q000166:cytology / Q000276:immunology*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism*; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D000099192:CD69 Antigens
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D016753:Interleukin-10; D037181:Lectins, C-Type; D008070:Lipopolysaccharides; D016692:Receptors, Antigen, T-Cell, gamma-delta; D012462:Saline Solution, Hypertonic; D014409:Tumor Necrosis Factor-alpha; D000099192:CD69 Antigens